KR20020003011A - Chemical Vapor Deposition apparatus comprising a united susceptor - Google Patents

Abstract

PURPOSE: A chemical vapor deposition chamber is provided to prevent a stacking of a powder contaminant materials in a circumference of a wafer loading surface in spite of forming in a materials film on an entire surface of the wafer in a uniformly thickness. CONSTITUTION: A chemical vapor deposition chamber is provided with a susceptor(40) including a wafer loading surface(40a), a spread head(42) opposite to the loading surface, and a heater(44) opposite to reverse surface of the wafer loading surface. A circumference of the wafer loading surface(40a) of the susceptor(40) is kept at the same temperature as the wafer loading surface and is sloped.

Description

Chemical Vapor Deposition apparatus comprising a united susceptor

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a chemical vapor deposition (CVD) chamber used in the manufacture of semiconductor devices, and more particularly, to a CVD chamber having an integrated susceptor.

In a wafer processing process such as a thin film deposition process or an etching process, the interior of the chamber is contaminated not only by the reaction by-products generated during the process but also by the source gas supplied to the chamber.

In the case of contamination by source gas, the degree of contamination varies depending on the characteristics of the equipment provided in the chamber rather than the source gas supply method.

Referring to FIG. 1, a conventional CVD chamber such as an Atmospherical Pressure Vapor Deposition (APCVD) chamber 10 includes a susceptor 12 having a wafer loading surface 12a therein. A dispersing head 14 for supplying a source gas to the entire surface of the wafer is provided below, and a heater 16 for heating the susceptor 12 to a temperature suitable for the process is provided thereon. In addition, a guide ring 18 is provided around the wafer loading surface 12a of the susceptor 12 to prevent the source gas supplied from the dispersion head 14 from flowing behind the susceptor 12.

2 is a temperature distribution diagram of a wafer loaded on the susceptor 12 during the BPSG film deposition process. In Figure 2 the horizontal axis and the vertical axis represent the temperature measurement position and the temperature measured at that position, respectively. The temperature measurement position on the horizontal axis is set to zero in the center of the wafer, and the change in position is set to positive in one selected direction from the center of the wafer toward the edge of the wafer and negative in the opposite direction. It is. Reference numeral W denotes a wafer section.

2, the temperature of the center of the wafer and the region close thereto is about 380 ° C to 430 ° C, but the edge temperature of the wafer is about 50 ° C lower than this. This result indicates that the temperature of the susceptor 12 is maintained at a temperature suitable for the process during the process, while the temperature of the guide ring 18 is relatively low such that the edge of the susceptor 12 abuts the guide ring 18. The temperature will be lower than the center temperature. This means that the edge temperature of the wafer is lower than the temperature of the wafer center and the region close thereto. As such, since the temperature distribution of the wafer is not uniform, it is difficult to form a material film having a uniform thickness over the entire wafer area.

3 is a cross-sectional view illustrating a flow of source gas introduced into a chamber. In FIG. 3, the first to third arrows A1, A2, and A3 denote source gases which are sequentially discharged through the source gas injected from the dispersion head 14, the wafer loading surface 12a, and the guide ring 18. A source gas is exhausted down along the side of the dispersion head 14.

Referring to FIG. 3, it can be seen that the source gas introduced into the chamber through the dispersion head 14 is injected toward the wafer loading surface 12a of the susceptor 12. Therefore, when the wafer is loaded on the wafer loading surface 12a, the source gas comes into contact with the wafer first, and then with the guide ring 18.

However, as described above, the temperature of the guide ring 18 is relatively lower than the temperature of the wafer loading surface 12a. Thus, the source gas which has not reacted with the wafer is rapidly cooled while in contact with the guide ring 18. This cooling effect causes the source gas to adhere to the guide ring 18 surface. As the source gas accumulates in the guide ring 18, a powdery material is deposited on the surface of the guide ring 18.

The inventors have used silicon carbide (SiC) instead of conventional quartz to determine whether such a powdery material is deposited on the surface of the guide ring 18 on the material of the guide ring 18. ), But it was unchanged that the powdery substance was laminated on the surface thereof.

These results show that the deposition of powdery material on the surface of the guide ring 18 is not a matter of the material of the guide ring 18 but is related to the temperature and flow of the source gas.

It is desirable to remove the powdery material deposited on the surface of the guide ring 18 because it acts as a particle in the wafer processing process and contaminates the wafer, which is an unexpected operation and consequently prevents preliminary maintenance of the components provided in the chamber. Maintenance (hereinafter referred to as PM) is shortened, and the time required for PM within a predetermined time (usually 24 hours), that is, PM rate is also increased. Thus, productivity is lowered.

Therefore, the technical problem to be achieved by the present invention is to solve the problems of the prior art described above, to enable the formation of a material film of uniform thickness on the entire surface of the wafer, and to provide a powdery material in the chamber inside during the wafer processing process. It is to provide a CVD chamber that can prevent the stacking.

1 is a schematic cross-sectional view of a chemical vapor deposition chamber according to the prior art.

FIG. 2 is a graph illustrating a temperature distribution of a wafer loaded in a chemical vapor deposition chamber according to the prior art illustrated in FIG. 1.

3 is a cross-sectional view illustrating a source gas flow in a chemical vapor deposition chamber according to the prior art shown in FIG. 1.

4 is a cross-sectional view of a chemical vapor deposition chamber having an integrated susceptor according to an embodiment of the present invention.

FIG. 5 is a graph showing a temperature distribution of a wafer loaded in a chemical vapor deposition chamber having an integrated susceptor according to the embodiment of the present invention shown in FIG. 4.

* Description of Signs of Major Parts of Drawings *

38: Chemical Vapor Deposition Chamber. 40: susceptor.

42: Dispersion head. 44: Heater.

40a: Wafer loading surface. 40b: Inclined surface.

θ: angle of inclination.

In order to achieve the above technical problem, the present invention provides a CVD chamber having a susceptor having a wafer loading surface, a dispersion head facing the wafer loading surface, and a heater facing the wafer loading surface opposite to the wafer loading surface. And a circumference of the wafer loading surface of the susceptor is maintained at an identical temperature to the wafer loading surface and is inclined.

In this case, the inclined portion around the wafer loading surface is connected to the wafer loading surface and the edge of the susceptor as part of the susceptor, and the circumference of the wafer loading surface of the susceptor is inclined at 20 ° to 45 °.

As such, the CVD chamber of the present invention has an integrated susceptor that also serves as a conventional guide ring. Thus, not only the wafer loading surface but also the circumference thereof can be maintained at the same temperature during the wafer processing process, thereby preventing the powdery material from being deposited around the wafer loading surface. As a result, the wafer can be prevented from being contaminated back by the powdery substance, the PM cycle of the equipment in the chamber can be long, and the PM rate is also lowered.

Hereinafter, a CVD chamber having an integrated susceptor according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

In the process, the thicknesses of layers or regions illustrated in the drawings are exaggerated for clarity. In the drawings, like reference numerals refer to like elements.

Referring to FIG. 4, a susceptor 40 is provided in the CVD chamber 38. The susceptor 40 is an integrated susceptor. That is, the means itself is provided with a role of a conventional guide ring. A dispersing head 42 for injecting a source gas under the susceptor 40 is provided. The wafer loading surface 40a on which the wafer is loaded is formed on the surface of the susceptor 40 that faces the dispersion head 42. An inclined surface 40b connected to an edge of the susceptor 40 is formed around the wafer loading surface 40a of the susceptor 40. The inclination angle θ of the inclined surface 40b is about 20 ° to 45 ° with respect to the wafer loading surface 40a. The inclined surface 40b serves as a conventional guide ring. That is, the source gas injected to the outside of the wafer loading surface 40a of the susceptor 40 is prevented from flowing back to the wafer loading surface 40a by the inclined surface 40b. As shown in the drawing, the inclined surface 40b is connected to the wafer loading surface 40a as well as the edge of the susceptor 40. In this way, the inclined surface 40b is not separated from the susceptor but is integrated with the susceptor 40. For this reason, the susceptor of the present invention is called an integrated susceptor.

Subsequently, the heater 44 is provided on the susceptor 40. The heater 44 serves to heat the susceptor 40 through a surface opposite the wafer loading surface of the susceptor 40. Since the susceptor 40 is integral, the entire area of the susceptor 40 is heated to the same temperature. That is, not only the wafer loading surface 40a but also the inclined surface 40b are heated to the same temperature.

Therefore, it can be seen that the temperature distribution of the wafer loaded on the wafer loading surface 40a of the susceptor 40 is uniform over the entire area of the wafer, as shown in the simulation result shown in FIG. 5. The result shown in FIG. 5 is a temperature distribution measured at a position spaced about 1 mm from the back surface of the wafer, and thus may be regarded as a temperature distribution of the wafer.

In FIG. 5, the horizontal axis represents a temperature measurement position, and the vertical axis represents a temperature according to the position. The temperature measurement position is zero at the center of the wafer, and the change in position is positive if it follows any selected direction from the center of the wafer to the edge, and negative if it is opposite the direction selected from the wafer center. It was. In the figure, reference numeral W1 denotes a wafer section.

Referring to FIG. 5, the temperature distribution of the wafer is uniform within 380 ° C. to 430 ° C. without region distinction. In the region off the wafer, the temperature distribution appears to drop sharply because the inclined surface 44b around the wafer loading surface 44a is spaced apart from the plane to which the wafer loading surface 44a belongs. Therefore, the temperature distribution measured at the surface of the inclined surface 44b will show the same distribution as the temperature distribution of the wafer.

As such, when the integrated susceptor 40 is used, since the temperature distribution of the wafer becomes uniform over the entire region, a material film having a uniform thickness can be formed over the entire wafer region.

Meanwhile, referring to FIG. 4, when the wafer is loaded on the wafer loading surface 40a, the source gas injected from the dispersion head 42 first faces the wafer loading surface 40a, and thus, the wafer loaded on the wafer loading surface 40a. Will react. The source gas that failed to react with the wafer is either exhausted out of the wafer or the dispersion head 42 is exhausted back along the side. In this process, the source gas and the inclined surface 40b react, the inclined surface 40b being part of the integrated susceptor 40 so that the temperature is the same as the wafer loading surface 40a. For example, the temperature of the inclined surface 40b is 400 ° C. Thus, although a material film, such as a BPSG film, is formed on the inclined surface 40b similarly to the wafer loading surface 40a, it is due to the temperature difference between the wafer loading surface and the member surrounding it, which is pointed out as a problem of the prior art. Cooling of the source gas can prevent the deposition of powdery material around the wafer loading surface.

The inventors are concerned that the non-powder-like material film deposited on the inclined surface 40b around the wafer loading surface 40a may have some influence on the material film forming process, but the inclined surface until the cleaning period of the susceptor 40 is maintained. There was no effect due to the material film deposited on 40b).

This means that no powdery material is deposited on the inclined surface 40b until the cleaning period of the susceptor 40. This also means that the PM rate is lowered.

Specifically, the cleaning cycle of the guide ring in the conventional CVD chamber is generally much shorter than the cleaning cycle of the susceptor due to the material film deposited on the inclined surface 40b until the cleaning cycle of the susceptor 40. The result of 'the effect is not shown' indicates that the susceptor 40 according to the present invention has the same effect as taking the cleaning cycle of the conventional guide ring as long as the cleaning cycle of the susceptor. Accordingly, since the PM frequency of the guide ring is lowered at the time of PM, the PM rate of the CVD chamber is lowered. In other words, since the use time for wafer processing of the CVD chamber is increased, the utilization efficiency of the CVD chamber is increased.

While many details are set forth in the foregoing description, they should be construed as illustrative of preferred embodiments, rather than to limit the scope of the invention. For example, a person having ordinary knowledge in the technical field to which the present invention belongs uses the conventional susceptor as it is, considering economic cost, and is formed of a material that can withstand the same temperature as the susceptor based on the technical idea of the present invention. It may be possible to tilt the surface while using the guide ring. Predictably, a guide ring made of the same material as the susceptor may be provided, but the surface of the guide ring may be inclined.

As described above, the CVD chamber of the present invention has an integrated susceptor that also serves as a conventional guide ring. Therefore, not only the wafer loading surface but also the circumference thereof can be maintained at the same temperature during the wafer processing process, so that a powdery substance can be prevented from being deposited around the wafer loading surface while forming a material film with a uniform thickness over the entire wafer surface. As a result, the wafer can be prevented from being contaminated back by the powdery substance, the PM cycle of the equipment in the chamber can be long, and the PM rate can be lowered.

Claims (3)

A CVD chamber comprising a susceptor having a wafer loading surface, a dispersion head facing the wafer loading surface, and a heater facing the wafer loading surface opposite the susceptor. And a circumference of the wafer loading surface of the susceptor is maintained at an identical temperature to the wafer loading surface and is inclined. The CVD chamber of claim 1, wherein the inclined portion around the wafer loading surface is connected to the wafer loading surface and the edge of the susceptor as part of the susceptor. The CVD chamber of claim 1, wherein a circumference of the wafer loading surface of the susceptor is inclined at 20 ° to 45 °.